SIZING UP A POND PUMP – PART TWO – How To Select The Right Pond Pump For Your Backyard Pond
Welcome back to Part Two of our mini series on sizing up a pond pump.
If you haven’t seen Part One, go check that out and then come back.
If you have seen Part One, view Part Two below:
SIZING UP A POND PUMP – PART TWO – How To Select The Right Pond Pump For Your Backyard Pond – Transcript
Sizing Up A Pond Pump
G’day this is Scotty Tucker,
So once you’ve got your estimated pond volume, let’s say for example it’s four thousand litres, what that means in theory is that you need a four thousand litre an hour pond pump.
Unfortunately, it’s still not that simple.
Because what you’re then going to use that pump for then starts determining and influencing the size that you actually need.
When you’re pumping water, and when you’re moving water around in a pond, if you put a four thousand litre pond pump in there, and the manufacturer’s specifications say that it’s a four thousand litre an hour pump, then hopefully you’ve got a good chance that it’s gonna move four thousand litres an hour.
Sometimes the manufacturers stretch the truth a little bit depending on where it’s made.
Chinese pumps are a little notorious for not doing what they actually say they’re going to do.
But lets say you get a reputable pump company who’s told you it’s a four thousand litre pump, you put it in a four thousand litre pond, and it’s moving four thousand litres an hour, that’s great!
Problem is, as soon as you start putting on a hose, and for example going up a waterfall, or statue, or whatever water feature you want to run or, going into a filter, what happens is that that pump loses some of that circulation because the trade off is, the higher you lift water, the less water that actually comes out the end when you lift it.
That’s the second specification that you’ll get on a pond pump.
They’ll generally have two main aspects that they’ll list on the box or on the packaging:
One will say four thousand litres an hour and it might say something like max head, 3.5m
What that means, head just simply refers to the height that the pump is gonna lift the water.
And that height isn’t taken all the way down from the bottom, it’s taken from the top water level.
So lets say for arguments sake, you’ve got a waterfall that’s one metre high and your pump says that it’s got a maximum head of 3.5m high.
You might think “Great, four thousand litres, maximum height it’ll do is 3.5m high, that’s the perfect pump for me.
Unfortunately it’s not.
Because that’s where the trade off comes in.
What happens is that the pump when it invests the energy in lifting the water up through the hose.
Then it has to, the trade off is, that some of the water flow is reduced.
So what happens, and you’ll see this on again, some of the pump packaging and websites, and information that you’ll see, is that you’ll have a pump performance chart, or a curve.
And that simply shows you how much water the pump will do at what they call zero metres head or no lift, which is that four thousand litres an hour.
And it will show you what it will do at the maximum height of 3.5m and what you’ll see at that maximum height of 3.5m is that no water comes out or the slightest trickle.
So in between there, if you’ve got a waterfall that’s say one metre high, what you’re gonna find is that that pump is probably gonna move, you know, maybe two thousand litres, maybe three thousand litres, at one metre high.
So coming back to that general rule of circulating the water body once an hour, you think you’ve got a four thousand litre pond, I need a four thousand litre pump, but because you’re going up a waterfall or a statue or up into a filter you need to allow for that and say well ok now it’s only gonna do somewhere between two to three thousand litres an hour so I need a larger pump.
And that’s a good general rule, if ever you’re not sure, but you know that your pond is four thousand litres, and you remember this video, just think ok I know I’ve got a four thousand litre pond but I’m gonna be pumping through a waterfall and this and that so I’m better off to step it up to a six thousand litre an hour pump, or a five thousand, or an eight thousand, whatever the next model up is, just so that you’ve got that extra capacity.
You can always turn a pump that’s more powerful down, but you can’t turn a pump up if it’s not giving you the flow that you want out of your waterfall or your filter.
So that’s the first stage if you’d like, on sizing up a pond pump.
Want to learn more and make sure you nail it?
Stay tuned for Part Three.